flake8-sqlalchemy

A flake8 plugin for SQLAlchemy code.

Installation

pip install flake8-sqlalchemy

Configuration

By default, all checks are enabled. You can disable all checks by adding the following to your setup.cfg:

[flake8]
ignore = SQA

or ignore specific checks:

[flake8]
ignore = SQA100

SQA100 - sqlalchemy import alias

Checks that when sqlalchemy is imported with an alias, the alias is either sa or db.

Bad

import sqlalchemy as foo

Good

import sqlalchemy as sa
# or
import sqlalchemy as db

SQA200 - Column keyword argument comment required

When writing a Column definition the comment keyword argument is required. This provides inline documentation for the column, as well as generating the SQL to add the comment to the database.

Bad

class Users(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True)
    name = Column(String)

Good

class Users(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True, comment="User ID from Auth Service")
    name = Column(String, comment="User name: first, middle, last")

Also applies to mapped_column:

class Users(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True, comment="User ID from Auth Service")
    name = mapped_column(String, comment="User name: first, middle, last")

SQA300 - Use back_populates instead of backref in relationship

Encourages the use of back_populates instead of backref in SQLAlchemy relationships to ensure clarity and consistency in bidirectional relationships.

Bad

class Parent(Base):
    __tablename__ = "parent"
    id = Column(Integer, primary_key=True)
    children = relationship("Child", backref="parent")

Good

class Parent(Base):
    __tablename__ = "parent"
    id = Column(Integer, primary_key=True)
    children = relationship("Child", back_populates="parent")

class Child(Base):
    __tablename__ = "child"
    id = Column(Integer, primary_key=True)
    parent_id = Column(Integer, ForeignKey("parent.id"))
    parent = relationship("Parent", back_populates="children")

License

This project is licensed under the terms of the MIT license. See the LICENSE file for the full license text.

Author

• Mike Fiedler